Fosfomycin

What it is used for

Fosfomycin Tromethamine is indicated only for the treatment of uncomplicated urinary tract infections (acute cystitis) in women due to susceptible strains of Escherichia coli and Enterococcus faecalis. Fosfomycin Tromethamine is not indicated for the treatment of pyelonephritis or perinephric abscess.

If persistence or reappearance of bacteriuria occurs after treatment with Fosfomycin Tromethamine, other therapeutic agents should be selected. (See PRECAUTIONS and CLINICAL STUDIES sections.)

How to take it

The recommended dosage for women 18 years of age and older for uncomplicated urinary tract infection (acute cystitis) is one sachet of Fosfomycin Tromethamine. Fosfomycin Tromethamine may be taken with or without food.

Fosfomycin Tromethamine should not be taken in its dry form. Always mix Fosfomycin Tromethamine with water before ingesting. (See PREPARATION section.)

Who should not take it

Fosfomycin Tromethamine is contraindicated in patients with known hypersensitivity to the drug.

Warnings

Clostridium difficile associated diarrhea (CDAD) has been reported with use of nearly all antibacterial agents, including Fosfomycin Tromethamine, and may range in severity from mild diarrhea to fatal colitis. Treatment with antibacterial agents alters the normal flora of the colon leading to overgrowth of C. difficile.

C. difficile produces toxins A and B which contribute to the development of CDAD. Hypertoxin producing strains of C. difficile cause increased morbidity and mortality, as these infections can be refractory to antimicrobial therapy and may require colectomy. CDAD must be considered in all patients who present with diarrhea following antibiotic use. Careful medical history is necessary since CDAD has been reported to occur over two months after the administration of antibacterial agents.

If CDAD is suspected or confirmed, ongoing antibiotic use not directed against C. difficile may need to be discontinued. Appropriate fluid and electrolyte management, protein supplementation, antibiotic treatment of C. difficile, and surgical evaluation should be instituted as clinically indicated.

Other medicines and interactions

Metoclopramide: When coadministered with Fosfomycin Tromethamine, metoclopramide, a drug which increases gastrointestinal motility, lowers the serum concentration and urinary excretion of fosfomycin. Other drugs that increase gastrointestinal motility may produce similar effects.

Cimetidine: Cimetidine does not affect the pharmacokinetics of fosfomycin when coadministered with Fosfomycin Tromethamine.

General

Do not use more than one single dose of Fosfomycin Tromethamine to treat a single episode of acute cystitis. Repeated daily doses of Fosfomycin Tromethamine did not improve the clinical success or microbiological eradication rates compared to single dose therapy, but did increase the incidence of adverse events. Urine specimens for culture and susceptibility testing should be obtained before and after completion of therapy.